Increased motion of air and/or fuel charge injected into an engine combustion chamber can increase combustion efficiency under some conditions. For example, charge motion can increase the effectiveness of combustion by introducing air velocity and turbulence in directions perpendicular to the flow direction. By introducing additional kinetic energy into the combustion chambers, an ignition front may traverse the volume of the combustion chamber more quickly and more evenly, so as to interact with a heightened amount of fuel before thermal energy is translated to piston motion. Further, resulting turbulence may increase homogenization of the air-to-fuel mixture within the combustion chamber as well as increase the burn rate, which is the time required for the air/fuel mixture to burn completely during the combustion process.
To improve charge tumble and swirl parameters, various motion control devices may be coupled upstream of the intake of engine cylinders. By varying the charge motion of a cylinder, the cylinder burn rate can be varied. One example motion control device is shown by Overbeck in U.S. Pat. No. 4,928,638. Therein, an individual variable bladder is placed within an engine intake runner. The tongue may be configured to have a variable cross-section, where the cross-section is varied based on engine operating parameters. Specifically, a degree of inflation of the bladder is adjusted to vary the degree of occlusion of the flow path available for an air-fuel mixture entering the intake manifold.
However, the inventor herein has recognized potential issues with such devices. As one example, in addition to being spatially constrained, the bladder may be prone to thermal degradation due to proximity of the bladder to the hot cylinder head. Further, proximity to the hot cylinder head may affect the ability to control the amount of inflation/deflation achieved. For example, bladder heating may result in more inflation than desired. As such, this may adversely affect a combustion air-fuel ratio control. As another example, the bladder of Overbeck affects the charge motion to all cylinders globally but may not be able to adjust the charge motion of each cylinder individually. As such, there may be conditions where certain cylinders demand more or less charge motion than other cylinders.
In one example, the issues described above may be addressed by a system including a cylinder with an intake runner, and a protrusion system positioned in an opening on a bottom wall of the intake runner nearest the cylinder, the protrusion system including a tongue movably positioned inside a spring-loaded casing, the spring-loaded casing anchored to a region of the bottom wall defining the opening. The system may include a controller storing non-transitory instructions in memory that when executed cause the controller to activate an actuator for positioning the tongue of the protrusion system outward from the spring-loaded casing through the opening on the bottom wall of the intake runner, responsive to an operating condition. The system may also include a second protrusion system, including a second tongue, the second tongue movably positioned inside a second spring-loaded casing, the second spring-loaded casing anchored to an upper wall of an intake manifold, the intake manifold fluidically connecting to the intake runner.
The above described approach may provide various advantages, including extending or retracting the tongue of the protrusion system may increase air/fuel mixing, and thereby, increase fuel economy. By using an actuator based efficient and compact protrusion system for extending the tongue of the protrusion system through an opening at the bottom wall of the intake runner, a desired tumble may be generated in the intake air charge. Additionally, the tongue may be adjusted based on sensed engine operations to optimize fuel efficiency of each individual engine cylinder.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.